The best map for the area is the one shown below, the OS explorer series 168
ISBN 0 - 319 - 21792 - 2
I have obtained a map of Nailsworth for the year 1884. Apparently, there are no copyright restrictions as it is over a hundred years old, so for your pleasure and enjoyment I have reproduced a section here. The section is the town centre, and the maps are 1024 x 768 pixels in size. I have set the jpg compression level such that detail is maintained, without losing quality.
Both images are of the same area, that of the town centre, the second image is zoomed in to show greater detail. Note that the large mill pond seems to be where the current bus station now stands! You may also note that the main road through the town is not shown.